Example embodiments relate to methods of manufacturing semiconductor devices.
Recently, as the integration degree of a semiconductor device has been increased, a channel length of a transistor has been decreased. Also, electrical characteristics of the semiconductor device have been degraded due to a short channel effect. Therefore, it is necessary to study methods of manufacturing semiconductor devices which may prevent degradation of the electrical characteristics of the semiconductor devices, may provide a predetermined punch through margin, and may reduce contact resistances of a source region and a drain region.